Master Cylinder 

• The master cylinder is usually located close to the firewall of the engine compartment and it may be connected to a brake booster or directly to the brake pedal
• The master cylinder is a device that converts force on the brake pedal into hydraulic pressure. It controls the slave cylinders located at the other end of the hydraulic brake system
• The master cylinder has a piston that moves inside a cylinder when the brake pedal is pressed, creating pressure in the brake fluid. This pressure is transmitted through the brake lines to the slave cylinders at each wheel, which apply braking force on the rotors or drums. The master cylinder has a reservoir that stores brake fluid and prevents air from entering the system